I have been using the magnetic ruler trick to check that the blade is parallel to the fence:

That method, as revealed by the tune-up done today using a dial indicator, isn’t very accurate.

I checked two settings of my Ridgid table saw: alignments of the miter slots to the blade, and to the fence.

The slots and the blade are accurate within 0.001”:

The slot and fence were way off by about 0.003” (that was also the factory setting!):

I immediately made adjustments to the the rip fence:

The alignment is close to perfect:

Close, because I found out the rip fence isn’t really dead-on uniformly straight along its face, or may be the miter slot isn’t. Since the error is within 0.001”, I am not going to worry about it. (Human hair is about 0.0039” in diameter.)

A dial indicator is a useful tool to double check or verify your settings.

-- The time I enjoy wasting is not time wasted

3 replies so far

Thanks for the info. I’ve learned that up to .004” away from the blade at the far end the fence is still safe. No tolerance is allowed towards the blade though because when the piece would pass through the blade it has a good chance to be caught by the tip of a tooth. This is real kickback potential.

I noticed in the fifth picture, you have the miter gauge and dial indicator registering off the right miter slot. Your readings are likely different than the rest because it is not uncommon that the two slots be slightly out of parallel.

Good point Chris. The reading on the right slot was off more than the left (which was 0.002+). After fine tuning, I brought the deviations on the slots to 0.001” and under 0.001” respectively.

Serge: Spot on about the kick-back danger if the the rip fence is skewed in the back towards the blade teeth. If the fence is skewed too much away from the blade in the back, however, it can lead to burn marks on the edge. I prefer a gap of 0.001” – 0.002” from the tooth in the back. I used a feeler gauge to double check the blade and the rip fence in the new setting and found the fence in the back was away from the blade tooth by almost 0.001”. May be 0.0005”. I tried to set it to 0.001”+ but then screwed up the whole alignment…at the end of the day, I redid everything and left it as was. (I shouldn’t have the feeler gauge around….)

Conclusion: Tuning up is very satisfying only after it’s done. The back-and-forth adjustments are definitely no fun. I think the next tune up will wait for a year or two….